Solid tumors metastasis

Many tumors are staged according to the tumor, nodes, metastases (TNM) system. Metastases are cancer cells that have spread to sites distant from the primary tumor site and have started to grow. The most frequently occurring sites of metastasis of solid tumors are the brain, bone, liver, and lungs. 

Ramaswamy S, Ross KN, Lander ES et al. A molecular signature of metastasis in primary solid tumors. 2003 33 49-54. 

On day 15, the solid tumor tissues were removed, and then cassigarol A was again administered orally twice daily for 17 days, starting 24 h after resection of tumor tissues on day 0. On day 18, the surviving tumor-removed mice were killed and the metastasis to the lung were observed. 

Metastasis, the spread of cancer cells from a primary tumor to remote sites in the body, is frequently the ultimate cause of death from solid tumors. Current options for treatment or prevention of metastasis are very limited. Since vascularization of tumors (angiogenesis) provides conduits required for the spread of the tumor cells to other sites (metastasis), targeting tumor vasculature not only offers a noncytotoxic approach to eradicating primary solid tumors, it should also aid in preventing their spread via metastasis. 

Miller, B. E., Aslakson, C. J. and Miller, F. R. (1990). Efficient recovery of clono-genic stem cells from solid tumors and occult metastatic deposits. Invasion Metastasis 10, 101-112. 

Whalen, G. F. and Sharif, S. F. (1992). Locally increased metastatic efficiency as a reason for preferential metastasis of solid tumors to lymph nodes. Aim. Surg. 215, 166-171. 

The basic differences between cancer cells and normal edh are uncontrolled cell proliferation, decreased cellular differentiation, ability to invade surrounding tissue, and ability ip establish new growth at ectopic sites (metastasis). Conuaiy to popular belief, not all tumor cells proliferate rapidly. Plv-liferation rates vary widely with the cell type. Thus, lymphomas and normal intestinal mucosa both proliferate fasui than. solid tumors. Acute leukemia cells actually prolifemc more slowly than the corresponding precursors in normal bone marrow. 

Although much is known about the processes of cancer formation, or carcinogenesis, comparatively little is known about the processes of cancer regression. The former will be explored as an introduction to the latter, and both involve the biological and chemical functions of the body, stated in terms of normal cells vs. cancerous ones. Surgical excision and radiation treatment are excluded from the discussion, though they can be selective if, say, the solid tumor is localized and has not yet spread or metastasized — and if the operations or treatments in themselves do not cause metastasis. 

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